Exploring the impact of nano-limestone cementitious material on mechanical, infiltration, and microstructure properties of pervious concrete

The impact of nano-limestone (NL) on the properties of pervious concrete (PC) is the focus of this study. The work explores workability, paste drain down, porosity via CT scanning, hardened density, mechanical strength, infiltration, and microstructural properties of PC. Field emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy facilitated the microstructural analysis. The findings verified that NL served as an inert substance that enhanced the density of the microstructure in PC. Moreover, it expedites cement hydration process by promoting the generation of nuclei at the boundaries. Different replacement rates of NL (1%, 2%, 3%, and 4%) were examined concerning cement. At a 2% NL replacement, the measured compressive strength of PC was 12.12 MPa and 24.29 MPa after 3 and 28 days, respectively. Splitting tensile strength recorded values of 1.62 MPa and 3.12 MPa, while shear strength measured 1.92 MPa and 3.75 MPa for the same periods. Significant enhancements were observed with compressive strength increasing notably by 48.2% after 3 days and 19.2% after 28 days. Similarly, the splitting tensile and shear strengths displayed remarkable increments of 48.6% and 16.4% after 3 days and 58.6% and 26.4% after 28 days, respectively. However, an increased NL percentage resulted in reduced permeability, rendering PC nearly impermeable at 4% replacement. The optimal NL percentage to maintain PC permeability was ≤ 2%, preserving an infiltration rate of 2.43 mm s⁻¹.